title: Topological quantum phase transitions on the kagomé and square-octagon lattices.
abstract: We study the topological quantum phase transitions of tight-binding electrons on two representative multi-band lattice models with superimposed staggered fluxes: the kagomé lattice and the square-octagon lattice. By considering the nearest-neighbor and next-nearest-neighbor hopping parameters (t1 and t2) and the staggered flux parameter φ, we obtain rich topological quantum phase transitions for both the lattices. The whole phase diagram for the kagomé lattice in the t2-φ parameter space is obtained. We also illustrate a series of topological quantum phase transitions as well as topological bands of high Chern numbers for the square-octagon lattice. Furthermore, interesting topological flat bands with high flatness ratios (e.g. of about 43) are found in the square-octagon lattice, especially when the next-next-nearest-neighbor hopping (t3) is included.
authors.affiliation: Center for Statistical and Theoretical Condensed Matter Physics, and Department of Physics, Zhejiang Normal University, Jinhua 321004, People's Republic of China.
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Liu
authors.forename: Wen-Chao
authors.initials: WC
authors.lastname: Chen
authors.forename: Yi-Fei
authors.initials: YF
authors.lastname: Wang
authors.forename: Chang-De
authors.initials: CD
authors.lastname: Gong